Figure 4. PEG-FGF2 conjugates promote the migration and proliferation of HDFs in vitro. (A ) Cellular proliferation activity of PEG-FGF2 conjugates was determined by CCK-8 assay using HDF cells. ***P < 0.001 vs. control group. Scale bar = 200 μm. (B, C ) Scratch wound healing assay of HDFs in the indicated groups for 36 h. The red dotted lines represent the wound boundary. Scale bar = 100 μm.*P < 0.05,***P < 0.001 vs. control group;##P < 0.01 vs. FGF2 group; n.s., no significance. All data are displayed as means ± SEM of 5 independent experiments.